1. Field of the Invention
This invention relates to trailers and, more particularly, to apparatus for steering trailers and for raising and lowering trailers.
2. Description of the Prior Art
U.S. Pat. No. 1,398,588 (Eccard) discloses a steering apparatus for a vehicle. Steering wheel geometry is illustrated.
U.S. Pat. No. 2,151,870 (Raven) discloses a trailer which may be raised and lowered using hydraulic cylinders.
U.S. Pat. No. 2,351,846 (Swim et al) discloses a trailer having a bed which is raised and lowered through linkage and the use of a single hydraulic cylinder.
U.S. Pat. No. 2,449,863 (Ross) discloses trailer apparatus using a hydraulic cylinder and structural linkages for raising and lowering the load carrying frame of a trailer.
U.S. Pat. No. 3,180,510 (Mollar) discloses a trailer for hauling a golf buggy. The trailer raises and lowers for loading and unloading a golf cart. It is actually the rear end of the trailer which tilts in response to hydraulic actuating cylinders. The tilting or movement of the trailer is accomplished by retracting its two wheels.
U.S. Pat. No. 4,109,811 (Stucky) discloses a trailer with a portion that is lowered by utilizing a pivoting arrangement between adjacent pairs of wheels. The adjacent pairs of wheels include a pivot axis and a second portion of the trailer apparatus also includes a pivot axis which allows a portion of the trailer bed to be lowered.
U.S. Pat. No. 4,706,987 discloses steering wheel geometry for a vehicle.
U.S. Pat. No. 4,934,733 discloses steering apparatus in a trailer.
U.S. Pat. No. 4,955,630 (Ogren) discloses a fifth wheel trailer steering mechanism. The steering mechanism includes a slide which is selectively engaged with and retracted from the fifth wheel of a tractor. Specific king pin geometry is disclosed.
U.S. Pat. No. 5,169,166 (Brooks) discloses steering apparatus for a skate board and the like. A steering apparatus is actuated by tilting of a board relative to the wheel and axle elements.
None of the patents described above includes elements for allowing the king pin of a trailer to move from a forward or positive caster to a negative caster for simplifying the steering of a trailer while the trailer is being backed.
Some of the patents disclose elements for raising and lowering trailer beds, but none of them include the simplified system illustrated in the apparatus of the present invention.
The invention described and claimed herein discloses trailer apparatus having pneumatic shock absorbers which perform a dual function of absorbing road shocks and of raising and lowering the trailer bed. The trailer apparatus also includes king pin elements which move between positive and negative caster to provide stability and ease of backing the trailer.
Among the objects of the present invention are the following:
To provide new and useful trailer apparatus;
To provide new and useful trailer apparatus having a bed which is able to be raised and lowered as desired;
To provide new and useful trailer apparatus having king pins movable between positive and negative caster;
To provide new and useful trailer apparatus having a tilting king pin assembly;
To provide new and useful trailer apparatus having a sliding king pin assembly; and
To provide new and useful trailer apparatus utilizing pneumatic shock absorbers for raising and lowering the bed of a trailer and having king pin assemblies movable between positive and negative caster inclinations to facilitate trailering and the backing of the trailer.